positionhigh has evolved the original MicroDexed port of the popular Yamaha DX7 plugin synth into a fully-blown, self-contained sample synth/sequencer/groovebox!

The project combines a Teensy 4.1 with a TI PCM5102A stereo DAC, and a capacitive touch ILI9341 SPI display. This upgraded design takes advantage of the PSRAM and SD Card on the Teensy 4.1 to have the ability to add samples during runtime. What began as Holger’s project to bring the DX7 sound to Teensy is now a complete workstation featuring a large TFT touch display. There is a long list of new features that includes an eight-voice polyphonic oscillator, a much improved sequencer, and many other improvements that bring this synth device to the next level.

External MIDI devices can be incorporated via USB or mini TRS jacks, including MIDI CC for controlling input/parameters. Samples can be loaded from SD card to PSRAM, the latter of which is also used to add up to 60 seconds of global delay effects. A tracker-styled editor and web-based remote control are in progress.

This versatile multi-function device device sounds amazing. Check out this YouTube video to hear what it’s capable of.

Code, documentation, STL files for a 3d-printed enclosure, and more can be found in the project’s Codeberg repo, and the PCB can be ordered directly from PCBWay.